Pressure sensors have achieved widespread acceptance for use in industrial applications. There are many pressure sensor variations, however most pressure sensors utilize some type of deflectable diaphragm that deflects when subjected to an applied pressure. Various techniques may be used to measure diaphragm deflection. For example, a strain gauge may be mounted to the diaphragm to provide an indication of deflection, or a piezoresistive capacitor may be used to measure deflection as deflection causes a change in capacitance. Nevertheless, pressure sensors come in many forms and may be tailored to meet specific needs of the industrial application.
An optical pressure sensor measures deflection caused by an applied pressure using an optical device, such as an interferometer. An interferometer measures light interference, which may be correlated to an applied pressure. Generally, an interferometer produces an input beam, splits it into two separate beams with a beam splitter, and recombines the beams on another beam splitter. Before recombining, each beam of light passes over a deflecting diaphragm, which creates interference and causes the power or the spatial shape of the beam to change. The interference of the recombined beam is then measured and correlated to an applied pressure.
Although there are many variations of optical pressure sensors, there is still a need in the art for highly sensitive optical pressure sensors that provide accurate pressure measurements. It is an object of the present invention to satisfy this need.